If the story is as it reads you got boned man. To a level you rarely see in the collaboration era. Cant believe your Fac Rep didn’t do more though the TRB process and especially after when the ATM went against the recommendation. The trainees and even your sup should have spoken up too if they thought you could certify in extension. You’re not a guy that everyone in the facility hates, are you? Z Fac Reps are busy but this is a career on the line. The Rep didn’t encourage you not to fight it did he? They pumped sunshine up some kids ass with a similar story about a year ago that they didn’t want to fight for, got him excited for the NEST even convinced him “it’s super easy to transfer” in the terminal environment.
Looks like the die has been cast if you are at the NEST step, I hope for the best but if your sup and trainers and Fac Rep who already screwed you wrote recommendation letters, I wouldn’t put much stock into that, as even when recommendation letters are “sincere” the NEST often shows no evidence of caring.
So I hope it works out, but back to the original question, it’s not unheard of but you would be fortunate to be offered a tower. The ATO found they can staff the hard to staff Flight Service and Air Traffic Assistant positions with people with zero Z certs so they often only offer that then NATCA tells you “you are lucky to still be offered a government job”.